Retarding device



G. F. C. BAUER RETARDING DEVICE Jan. 11, 1927.

5 Sheets-Sheet 1 Filed April 5, 1925 Jan. 1927'.

G. F. c. BAUER RETARDING DEVIGE 3 Sheets-Sheet 2 7 Filed April 5. 192'sPatented Jan. 11, ea.

UhllTE STATES PATNT OFFICE.

GUSTAV F. C. BAUER, OF TONAWANDA, NEW YORK, ASSIGNOR TO BOOK AS?HALT &CONSTRUCTION CO. INC., OF BUFFALO, NEW YORK, A CORPORATION OF NEW YORK.

RETARDING DEVICE.

Application filed April 3, 1925. Serial No. 20,507. a

This invention relates to a retarding device which is adapted to be usedfor a variety oi purposes but is more particularly intended for use inan automatic flasher of electric traffic control systems, said flasheroperating a visible signal located at a traflic crossing. This flasheris adapted to give alternating signals by which the traflic 1n onedirection is given a go signal while intersecting traflic is given astop indication, and upon reversing the signals ntersecting traffic ispermitted to cross while the main tratfic is given a warning signal tostop, a suitable audible and visible caution signal sometimes beinggiven to ndicate a. change of signals. WVhen used in such a system thisretarding device operates a system of electric switches (not shown) anddetermines the period of time during which each signal is held, and forthis purpose it is so designed that the time period of each signal canbe quickly changed independently of the other signal time period so thatthe traffie control system can be readily adapted to changing trafficconditions. .Thus at a certain crossing where the main traffic 1sheavier than the intersecting traffic, a longer time period can be givento the main tra'liic,

and at another crossing where the traflic conditions are equal the timeperiods of the signal can be made of equal length.

l urther objects of this invention are to provide a retarding devicewhich is of simple construction and not liable to get out of order oradjustment by continuous use and which is not affected by temperature orother climatic changes.

In the accompanying drawings:

Figure 1, is a longitudinal sectional elevation of the retarding deviceshowing the piston traveling in the direction of the arrovi associatedtherewith at a retarded speed.

Figure 2 is a. similar view showing the plunger traveling in theopposite direction 7 er speed. 7 Figure 3 is a side elevation of theretarding device showing the end heads in the same adjustment as inFigures 1 and 2.

Figure 4 is an end elevation thereof.

uro 5 is an end elevation of one of the heads.

a rare 6 is a longitudinal fragmentary sectional elevation of amodification of the sleeve supporting means.

Figure- 7 is afragmentary section showing a modification of theadjusting means.

Figure 8 is a transverse sectional elevation, the same being taken online 88, Fig. 7.

Figure 9 is a longitudinal section of a modified form of the retardingdevice showing the piston traveling in the direction of the arrowassociated therewith.

In its general organization the retarding device comprises a casing orcylinder containing a fluid in which is arranged a plunger reciprocatedagainst the resistance of the fluid, and by-pass means formed in thecasing whereby the fluid is forced from one end of the cylinder totheother, the rate of flow of the fluid through the by-pass beingadjustably controlled by a controller which covers the by-pass and isreciprocated by the alternating pressure of the fluid suitable portsbeing provided ateach end of the controller which give a variableresistance to the flow of fluid depending upon the longitudinal movementof the controller which is controlled by movable abutments arranged ateach end of the casing.

In the preferred embodiment of this invention, as shown inFigures 1, 2,8, 4t and 5, the enclosing casing 10 is of cylindrical form and isprovided on one side with an integral bracket 11 having transverse holes12 by which it may be secured to an adjacent wall or stationary part inany suitable manner. Both ends of this cylinder are provided withexternally threaded reduced portions 13 on which are secured the endscrew collars l4. lVithin the casing and extending outward from thebore'thereot' is a central annular recess 15 forming a b-y-pass whichextends adjacent the ends of the easing and forms a channel throughwhich the fluid with which the casing is filled passes from one side ofthe plunger head to the other as it is reciprocated.

The controllingsleeve 16 by which this flow is regulated is arrangedwithin the easing and is supported at its opposite ends in the borethereof bridging the annular recess 15. In order to limit the movementof the sleeve end heads or abutments 17 and 18 are luu provided, each ofwhich is externally threaded adjacent its outer end and is adapted toengage the corresponding internally threaded outer end 19 of therespective screw collar 14:. The intermediate portion 20 of each ofthese heads is of somewhat greater diameter than the bore of thecylinder and forms an annular shoulder 21 which is adapted to engage theend of the cylinder and thereby limit the inward movement of theadjusting head. To prevent leakage of the fluid from the interior of thecasing past the end heads a ring 22 of packing is provided between eachhead and the casing which is compressed between a longitudinally outwardextending annular flange 43 provided on the casing and a radiallyinwardly extending flange or bead 24 provided on the screw collar. Thescrew collars 1 1 therefore serve to compress the packing, withouthowever affecting the limit of movement of the adjusting head, sincethis is determined by the engagement of the shoulder 21 with the easing.On the rim of the inner end 25 of each of the adjusting heads andprojecting within the bore of the casing a plurality of stop lugs 26 areprovided which extend inwardly from said rim and form a seat or stop forthe sliding sleeve 16. By providing these lugs the adhesion between theend heads and the contacting sleeve is reduced rendering the sleeve moresensitive to slight pressures.

The plunger comprises a head or piston 27 which is arranged within thecylindrical bore of-the sleeve and adapted to reciprocate therein, and alongitudinal rod 28 secured to said plunger head by a nut 29, which rodextends through the adjusting head 18. The rod and plunger head may bereciprocated by any suitable yielding pressure means (not shown) so thatthe rate of travel of the plunger is affected by the resistance offeredby the fluid in the casing. A stu'l'ling box of any suitable form may beprovided to prevent leakage of the fluid past the plunger rod, thatshown comprising an externally threaded gland 30 arranged around thepiston rod and screwing into a recess 31 in which is arranged suitablepacking 32.

The opposite head 17 is hollow or dished inwardly forming a recess 33 inwhich is arranged a screw 3a which closes an opening extending throughthis head to the interior of the casing. The fluid is introduced throughthis opening into the casing when this becomes necessary.

The sleeve 16 has a relatively slight longitudinal movement and bears onthe inwardly extending annular rims 35 and 36 formed by the recess 15,the intermediate portion 37 of the sleeve being of smaller diameter thanits ends 38 and 39 to facilitate removal and insertion of the same. Atopposite ends of the sleeve beyond the path of the plunger head seriesof ports 40 and 41 are provided which extend radially through the sleeveand each arranged in a spiral line around the same, the pitch of thesame being exaggerated for the purpose of illustration. Each of theseseries of ports is adapted to register with and be covered to a greateror less extent by the adjacent rim 35 or 36 according to the adjustmentof the adjacent adjusting head and thereby increase the resistance tothe flow of the fluid from one side of the plunger, through the sleeveand recess 15 to the other side of said plunger. Ad justmont of the endheads for this purpose is facilitated by providing each of the same witha handle or lever i2 having a flat arcuate portion at?) which is adaptedto be secured to the outer side of the head by a plurality of screws 41.

Assuming the end heads to be adjusted, as shown in Figures 1, 2 and 3 i.e., the end head 17 screwed inwardly only a short distance while the endhead 18 is adjusted inwardly to its maximum extent, the operation of theretarding device is as follows:

As the plunger moves in the direction of the end head 18, as indicatedby the arrow at associated with the piston rod in Figure 1, the fluid inthat end of the casing within the sleeve is put under pressure, whilethe fluid pressure on the other side is come spondingly reduced, itbeing understood that the ports of the sleeve at all times offer asubstantial resistance to a free flow of fluid. Since the sleeve is freeto move longitudinally, this difference in pressure forces the sleevetoward the head 17 in the direction of the small arrow Z) in Figure 1until the same abuts against the stop lugs 26 provided on said head, asshown in Fig. 1, this sleeve operating in the same manner as an ordinarypiston valve put under pressure. As the head 17 has been adjustedoutwardly, as cont pared with the adjustment of the head 18, it isobvious that the sleeve moves a greater distance toward the head 17relative to the transverse center line of the annular recess than towardthe head 18. For the same reason when the sleeve abuts against the head17 a large number of ports are covered by the bore of the rim 35, asshown by the dotted line 45 indicating the end ofthe recess, and theflow of the fluid from the advancing side of the piston through theports d1, which are fully exposed, the recess 1.5 1

and through the open ports 10 to the trailing side of the piston isobviously impeded by the resistance offered by these last mentionedports.

When the plunger reaches he end of its stroke and reverses, as shown inFig. 2, the pressure built up in front of the plunger forces the sleevein the opposite direction against the head 18. Since this head isadjusted inwardly its maximum extent, none of the ports 11 are coveredby the bore of luu the casing, and the resistance to the fiow of fluidbeing correspondingly reduced, the speed of the piston in that directionis increased accordingly.

It is apparent that the adjustment of each head afiiects the number ofports closed by by the casing and that the speed of the piston isthereby capable of very fine regulation. It is also apparent that inthis device the regulation of the rate of travel of the piston in onedirection is wholly independent of the regulation of its speed in theopposite direction since the adjustment of one of the end heads does noteffect the number of ports covered when the piston reverses itsmovement. The fluid used in the retarding device is, of course,dependent upon the purpose for which the device is used but preferablyshould be of such a character that it is not affected by tempera turechanges or liable to change or deteriorate from other causes. It hasbeen found that certain grades of lubricating oils are a verysatisfactory fluid for this purpose.

Any suitable means may be provided for compensating for the oildisplaced by the body of the plunger rod 28 as it is moved in and out ofthe cylinder. This means, as shown in Figs. 1, 2 and 3 comprises an oilcup 80 provided on the upper side of the cylinder casing, the neck ofwhich is received in a threaded opening 81 extending through the casing.This oil cup is preferably provided at its upper end with a removablecap 82 which screws over the same and is provided with a vent opening83extending therethrough. The cup is of such I a size that it will containall of the oil displaced by the plunger rod so that as the rod movesinto the cylinder the oil rises in the cup expelling the air thereinthrough the vent opening and as the rod is moved out, the oil is drawnfrom'the cup back into the cylinder, and the cup is again filled withair. Providing an oil cup of this character also compensates forexpansion and contraction of the'liquid when the same is heated orchilled and thereby reduces the danger of the oil being forced out ofthe cylinder past the stufiing box and heads and being thereby lost.Inasmuch as the operation of the retarding device is due to thedifference in pressure at the advancing and following end of theplunger, the provision of such an oil cup for receiving the oildisplaced by the plunger rod has no effect upon the retarding action ofthe same.

In the modification shown in Figure 6 the casing is provided with acylindrical bore 46 threaded at its opposite ends. The sleeve issupported in the casing by externally'threaded supporting rings 47 whichengage the threaded part of the casing and correspond to the rims and 36in the preferred construction. The packing i8 is arranged outside ofeach of these rings and is compressed by an externally threaded packingring 49. In other respects this form is similar in construction andoperation' to the preferred form.

Figures 7 and 8 show a modification which is intended to reduce the lossof fluid from the casing. In this form the adjusting head 170 isentirely enclosed and has a threaded rim which engages an internallythreaded recess 51 of the casing so that upon turning the head alongitudinal adjustment is effected. To turn the head the same isprovided with a rim 52 at its rear end provided with gear teeth whichteeth are engaged by a pinion 53 which is of sutiicicnt length to ensureengagement of the teeth in any adjustment of the head. Over the end ofthe casing a cover or head Set is secured by bolts 55 or other suitablefastenings. The pinion is mounted on a shaft or pin 56 which isjournaled in the casing and extends through the cover 5%.- and is turnedby a knurled adjusting wheel 57, a suitable stuffing box 58 beingprovided to prevent leak age of the fluid at this point. By thisarrangement the danger of losing the fluid past the head is reduced andit is also possible to secure a much finer adjustment of the head.

A further modification is shown in Figure 9 which is adapted to be usedwhen the fiuid pressure caused by the movement of the piston is verylow. In this form the plunger operates in a separate cylinder 59 abovewhich a cylinder is provided in which the controlling sleeve 67 isarranged. Passages 66 are provided which permit an in tercommunicationof the fluid at both ends of the cylinders so that the movement of thepiston in either direction influences the sleeve 67. The latter ispreferably arranged substantially central of its cylinder and isprovided with an integral web GS-iutermediate its two series ofspirallyarranged ports 69 and 70 and an annular recess 71 is provided similar tothe annular recess 15 in the other forms of this invention. The meansfor limiting the longitudinal movement of the sleeve and thereby reulating the adjusting heads in the preferred construction, i. e.',determine the number of ports through which the fluid can flow when the.sleeve is forced against said screws by the fluid pressure. Suitablestufiing boxes 76 are provided for each of these screws and ion liii

also for the plunger rod to prevent loss of the fluid.

In this construction, instead of providing an oil cup to compensate forthe oil dis-placed by the plunger rod 28, the shaft is extended beyondthe plunger head If in the form of an extension 84, which extension isguided in the head 74 and is of such a length that the outer end thereofis always arranged out side of the casing. A stufling box 85 is providedfor this extension similarto the stufting box 30 of the plunger or"aower shaft. Inasmuch as the plunger shaft 28 and the extension 8% areof equal diameter, as the shaft 28 moves into the cylinder, the oildisplaced thereby is exactly compensated for by the extension 84 whichis moving out of the cylinder at precisely the same rate of speed, andthereby balances the operation of the retarding device.

In the preferred construction, shown in Figs. l5, the cross sectionalarea against which the fluid pressure is effective in moving the sleevereversely to the plunger, is relatively small and it is hence obviousthat where the pressure operating the piston is very small the separatesleeve and cylinder construction shown in Fig. 9 will be more effectiveand positive since the fluid pressure acts on a greater area of thesame.

This invention provides a very simple, inexpensive and durable devicefor retarding the motion of the transmitting rod in either direction, itcan be quickly adjusted to meet varying conditions, and is not likely toget out of adjustment by ordinary use. It also requires little attentionand is not affected by temperature changes, etc., rendering it usefulfor many other purposes than that specified.

I claim as my invention 1. In a retarding device, a casing adapted tocontain a fluid, a plunger reciprocable in said casing against theresistance of said fluid, means permitting said fluid to pass from oneside of said plunger to the other, and means for retarding the flow offluid from one side of the plunger to the other on each stroke thereofcomprising a reciprocating member actuated by the reversing pressures ofsaid fluid.

2. In a retarding device, a cylinder containing a fluid, a plungerreciprocated against the resistance of said fluid, a loosely arrangedmember adapted to resist and thereby control the flow of fluid from oneside of said plunger to the other, said member being movable by thepressure of the fluid into a position in which the flow of fluid. in thecorresponding direction is regulated, and movable by the reverse fluidpressure into a position in which it controls the flow of fluid in thereverse direction, and means controlling the movement of said member andregulating the resistance ofl'ered thereby to the flow of fluid ineither direc tion.

3. In a retarding device, a cylinder containing a fluid, a plungerreciprocated against the resistance of said fluid, a loosely arrangedmember adapted to resist and thereby control the flow of fluid from oneside of said plunger to the other, said member being movable by thepressure of the fluid into a position in which the flow of fluid in thecorrespondin direction is regu lated, and movable by the reverse fluidpres sure into a position in which it controls the flow of fluid in thereverse direction, and means arranged at one end of said incur her forcontrolling its longitudinal movement and thereby control the flow offluid in the corresponding direction, and means arranged at the otherend of said member for sii'nilarly controlling the flow of fluid in theopposite direction.

l. In a retarding device, a casing adapted to contain a fluid, a plungerreciprocable in said casing against the resistance of said fluid, saidcasing having a by-pass around said plunger, and means for retarding theflow of fluid through said by-pass comprising a sleeve arranged oversaid by pass, said sleeve being reciprocated by the alternating pressureof the fluid so that this sleeve moves opposite to the movement of thepiston.

5. In a retarding device, a casing containing a fluid, a plungerreciprocated in said casing against the resistance of said fluid, saidcasing being provided with a by-pass through which the fluid is forcedfrom one end of said plunger to the other, and a sleeve covering saidby-pass and reciprocated by the alternating pressure of said fluid sothat this sleeve moves opposite to the movement of the piston, saidsleeve having ports adapted to register with said bypass and retard theflow of the fluid through the same.

6. Ina retarding device, a. :asing containing a fluid, a plungerreciprocated in said casing against the resistance of said fluid, saidcasing being provided with a recess through which the fluid flows fromone side of said plunger to the other side thereof, and a sleevecovering said recess and reciprocated by the alternating pressure ofsaid fluid, said sleeve having ports adjacent each of its ends whichports are adapted to register with saidrecess and retard the flow of thefluid through are same.

7. In a retarding device, a casing containing a fluid, a plungerreciprocated in said casing against the resistance of said fluid, saidcasing being provided with an annular recess through which the fluidflows from one side of said plunger to the other side thereof, a sleevereciprocated by the alternating pressure of said fluid and bridging saidannular recess, said sleeve having a series of ports adjacent each ofits ends each series being arranged spirally around'said sleeve, andadjustable means for limiting the movement of said sleeve in eitherdirection.

8. In a retarding device, a casing containing a. fluid, a plungerreciprocated in said casing against the resistance of said fluid, saidcasing having a cylindrical bore provided with an annular recess throughwhich recess the fluid is forced from one side of said plunger to theother, a sleeve arranged within the bore of said casing and bridgingsaid recess, said sleeve being reciprocated by the alternating pressureof said fluid, and said sleeve having a series of ports at each of itsends through which the fluid is forced through said recess, each of saidseries being arranged spirally around said sleeve, and a movableabutment arranged at each end of said sleeve and each adjustablylimiting forward movement in either direction where by the sleeve may bepermitted to slide into a position in which a number of ports at theadvancing end of the same register with the bore of the casing.

9. In a retarding device, a casing containing a fluid, a plungerreciprocated in said casing against the resistance of said fluid, saidcasing having a cylindrical bore provided with an annular recess throughwhich recess the fluid is forced from one side of said plunger to theother, a sleeve arranged within the bore of said casing and bridgingsaid recess, said sleeve being reciprocated by the alternating pressureof said fluid, and said sleeve having a series of ports at each of itsends through which the fluid is forced through said recess, each of saidseries being arranged spirally around said sleeve, and

a movable abutment arranged at each end of said sleeve and eachadjustably limiting its forward movement in either direction whereby thesleeve may be permitted to slide into a position in which a number ofports at the advancing end of the same register with the bore of thecasing, each of said movable abutments being adjustable independently ofthe other.

10. In a retarding device, a casing containing a fluid, a plungerreciprocated in said casing against the resistance of said fluid, saidcasing having a cylindrical bore provided with an annular recess throughwhich recess the fluid is forced from one side of said plunger to theother, a sleeve arranged within the bore of said casing and bridgingsaid recess, said sleeve being reciprocated by the alternating pressureof said fluid, and said sleeve having a series of ports at each of itsends through which the fluid is forced through said recess, each of saidseries being arranged spirally around said sleeve, and a movableabutment arranged at each end of said sleeve and each adjustablylimiting its forward movement in either direction whereby the sleeve maybe permitted to slide into a position in which a number of ports at theadvancing end ofthe same register with the bore of the casing, each ofsaid movable abutments being adjustable independentlyof the other andcomprising a'threaded member engaging said casing. i

11. In a retarding device, a cylinder containing a fluid, a plungerarranged in said cylinder and reciprocated agalnst the resistance ofsaid fluid, said cylinder being provided with by-pass meanscommunicating with the chamber of said cylinder on opposite sides ofsaid plunger, and means for retarding the flow of fluid through saidbypass comprising av sleeve arranged in sa d cylinder and covering saidbypass, said sleeve being reciprocated by the alternating pressure ofsaid fluid, and said plunger operating within said sleeve.

12. In a retarding device, a cylinder containing a fluid, a plungerarranged in sald cylinder and reciprocated against the resistance ofsaid fluid, said cylinder being provided with by-pass meanscommunicating with the chamber of said cylinder on opposite sides ofsaid plunger, means for retardingthe flow of fluid through said by-passcomprising a sleeve arranged in said cylinder and covering said by-pass,said sleeve being reciprocated by the alternating pressure ofsaid'fluid, and said plunger operating within said sleeve, adjustablemeans for limiting the longitudinal movement of said sleeve in onedirection, and adjustable means for limiting the longitudinal movementin the other direction.

13. In a; retarding device, a cylinder containing a fluid, a plungerarranged in said cylinder and reciprocated against the resistance ofsaid fluid, said cylinder being provided with an annular recess in itsbore, said recess forming a by-pass communicating with the chamber onopposite sides of said plunger and means for retarding the flow of fluidthrough said recess comprising a sleeve bridging said recess and adaptedto be reciprocated relatively thereto by the alternating pressure ofsaid fluid, said sleeve having a series of ports at each of its endsthrough which the fluid is forced through said recess, each of saidseries being arranged spirally around said sleeve adjacent the ends ofthe recess, and a movable abutment arranged ateach end of said sleeveand adjustably limiting its forward movement in either direction wherebythe sleeve may be permitted to slide into a position in which a, numberof ports at the advancing end of the same register with the bore of saidcylinder, said plunger operating with said sleeve intermediate saidseries of ports. v

14, In a retarding device, a cylinder containing a fluid, a plungerarranged in said cylinder and reciproeated against the resistance ofsaid fluid, said cylinder being provided with an annular recess in itshere, said recess forming a by-pass communicating with the chamber onopposite sides of said plunger and means for retarding the flow of fluidthrough said recess compr sing a sleeve bridging said recess and adaptedto be reciprocated relatively thereto by the alternating pressure ofsaid fluid, said sleeve having a series of ports at each of its endsthrough which the fluid it forced through said recess, each of saidseries being arranged spirally around said sleeve ad a-cent the ends ofthe recess, and a longitudinally movable abutment arranged at each endof said sleeve and adjustably limiting its forward movement in eitherdirection whereby the sleeve may be permitted to slide into a positionin which a number of ports at the advancing end of the same registerwith the bore of said cylinder said plunger operating with-in saidsleeve intermediate said series of ports and each of said abutmentscomprising a threaded head arranged in the corresponding end of saidcasing and adapted to be screwed longitudinally relatively thereto.

15. In a retarding device, a cylinder containing a fluid, a plungerarranged in said cylinder and reciprocated against the resistance ofsaid fluid, said cylinder being provided with an annular recess in itsbore, said recess forming a by-pass communicating with the chamber onopposite sides of said plunger and means for retarding the flow of fluidthrough said recess comprising a sleeve bridging said recess and adaptedto be reciprocated relatively thereto by the alternating pressure ofsaid fluid, said sleeve having a series of ports at each of its endsthrough which the fluid is forced through said recess, each of saidseries being arranged spirally around said sleeve adjacent the ends 01the recess, and a longitudinally movable abutment arranged at each endof said sleeve and adjustablylimiting its forward movement in eitherdirection whereby the sleeve may be permitted to slide into a positionin which a number of ports at the advancing end of the same registerwith the bore of said cylinder said plunger operating within said sleeveintermediate said series of ports and each of said abutments comprisinga threaded head arranged in the corresponding end of said casing andadaptcd to be screwed longitudinally relatively thereto and said headbeing provided on its inner end adjacent the bore of said cylinder witha plurality of lugs against which said sleeve is adapted to bear.

16. In a retarding device, a cylinder containing a fluid, a plungerarranged in said cylinder and reciprocated against the resistance ofsaid fluid, said cylinder being provided with an annular recess in itsbore,

said recess forming a by-pass communicating with" the chamber onopposite sides ol said plunger and means for retarding the flow of fluidthrough said recess comprising a sleeve bridging said recess and adaptedto be reciprocated relatively thereto by the alternating pressure ofsaid fluid, said sleeve having a series of ports at each of its endsthrough which the fluid is forced through said recess, each of saidseries being arranged spirally around .said sleeve adjacent the ends ofthe recess, and a longitudinally movable abutment arranged at each endof said sleeve and adjustably' limiting its forward movement in eitherdirection whereby the sleeve may be permitted to slide into a positionin which a number of ports at the ad vancingend of the same registerwith the bore of said cylinder said plunger operating within said sleeveintermediate said series of ports and each of said abutments comprising:1 threaded head arranged in the correspond ing end of said casing andadapted to be screwed longitudinally relatively thereto and said headbeing provided with a shoul der adapted to engage said cylinder andlimit the inward movement of said head.

17. In a retarding device, a cylinder containing a fluid, arplungerarranged in said cylinder and reciprocated against the resistance ofsaid fluid, said cylinder being provided with an annular recess in itsbore, said recess forming a by-pass communicating with the chamber onopposite sides of said plunger and means for retarding the flow of fluidthrough said recess comprising a sleeve bridging said recess and adaptedto be reciprocated relatively thereto by the alternating pressure ofsaid fluid, said sleev having a series of ports at each of its endsthrough which the fluid is forced through said recess, each of saidseries being arranged spirally around said sleeve adjacent end of therecess, and means for lim' ig the longitudinal movement of said sleevein either direction comprising an internally threaded collar secured toeach end of said cylinder, an externally threaded head engaging each orsaid internally threaded collars and adapted to be screwedlongitudinally relatively to said casing, said head extending into thebore of said cylinder and forming a movable abutment for said sleevewhereby the sleeve may be permitted to slide into a position in which anumber of ports at the advancing end of the same register with the boreof said cylinder said plun or operating within said sleeve intermediatesaid series of ports.

18. in a retarding device, a cylinder containing a fluid and havinginternally threaded ends, a plunger reciprocatcd in said cylinderagainst the resistance of said fluid, the bore of said cylinder beingprovided with an annular recess through which recess the vll) fluid isforced from one side of said plunger to the other, a sleeve arrangedwithin said cylinder and bridging said recess, said sleeve beingreciprocated by the alternating pres sure of said fluid and said sleevehaving a series of ports at each of its ends through which the fluid isforced through said recess, each of said series being arranged spirallyaround said sleeve, an externally threaded cylindrical adjusting headarranged at each end of said cylinder within the bore of the same andengr re; the internally threaded cnls thereof, ea

on of said adjusting heads being adapted to be moved longitudinally andadjustably limit the forward movement of said sleeve in either directionwhereby the sleeve may be permitted to slide into a position in which anumber of ports at the advancing end of the same register with the boreof said cylinder, and means for moving each of said adjusting headslongitudinally relatively to said cylinder comprising a plurality ofgear teeth arranged on the periphery of said head, a pinion engagingsaid teeth, and means arranged without said cylinder for turning saidpinion.

19. In a retarding device, a cylinder containing a fluid and havinginternally threaded ends, an externally threaded ring arranged in eachend of said cylinder and engaging the threaded portion thereof, saidrings forming an annular by-pass therebetween. a sleeve arranged withinsaid cylinder and supported by said threaded rings, a plunger arrangedin said sleeve and reciprocated against the resistance of said fluid,said sleeve being reciprocated by the alternating pressure of saidliquid and said sleeve having a series of spirally disposed ports ateach of its ends adjacent said threaded rings through which said liquidis forced through said by-pass, an externally threaded adjusting headengaging each internally threaded end of said cylinder and having itsinner end arranged within said threaded ring and adapted to adjustablylimit the forward movement of said sleeve in either direction, and meansfor moving said adjusting head longitudinally relatively to saidcylinder whereby the sleeve may be permitted to slide into a position inwhich a number of ports at the advancing end of the same register withthe bore of said threaded rings.

20. In a retarding device, a cylinder containing a fluid, a plungerreciprocated in the chamber of said cylinder against. the resistance ofsaid fluid, a bypass cylinder having a chamber communicating with thechamber of said first named cylinder on opposite sides of said plunger,and a loosely ai 'anged member arranged in said by-pass rylinder andreciprocated by the alternating pressure of said fluid so thatsaidmember moves opposite to the piston, said member being adapt-ed toretard the flow of fluid in both directions through said chamber.

21. In a retarding device, a cylinder containing a fluid, a plungerreciprocated in the chamber of said cylinder against the resistance ofsaid fluid, a by-pass cylinder having a' chamber communicating with thechamber of said first named cylinder on opposite sides of said plungerand said bypass chamber having a recess, and a sleeve reciprocted by thealternating pressure of said fluid arranged over said recess and havingports at its opposite ends adapted to permit a flow of liquid throughsaid recess, and a web arranged centrally within said sleeve andpreventing a direct flow of fluid therethrough.

22. In a retarding device, a cylinder containing a fluid, a plungerreciprocated in the chamber of said cylinder against the resistance ofsaid fluid, a by-pass cylinder having a chamber communicating with thechamber of said first named cylinder on opposite sides of said plungerand said bypass chamber having a recess, and a sleeve reciprocated bythe alternating pressure of said fluid arrangd over said recess andhaving ports at its opposite ends adapted to permita flow of liquidthrough said recess, a web arranged centrally within said sleeve andpreventing a direct flow of fluid therethrough, and adjustable meansengaging said web and limiting the longitudinal movement of said sleevein either direction.

23. In a retarding device, a cylinder containing a fluid, a plungerreciprocated in the chamber of said cylinder against the resistance ofsaid fluid, a by-pass cylinder having a chamber communicating with thechamber of said first named cylinder on opposite sides of said plungerand said bypass chamber having an annular recess, and a loosely arrangedsleeve reciprocated by the alternating pressure of said fluid and havinga series of spirally disposed ports at each of its ends adapted topermit aflow of liquid through said recess and means arranged at eachend of said sleeve for adjustably limiting its longitudinal movement ineither direction whereby the sleeve may be permitted to slide into aposition in which a number of ports at the advancing end of the same arecovered by the adjacent wall of the chamber in which said sleeveisarranged and the flow of fluid through the same correspondinglydecreased.

24. In a retarding device, a chamber adapted to contain a fluid, apiston movable back and forth in said chamber and dividing the same intocompartments, and bypass means whereby said compartments communicatewith each other and which operate to permit the fluid to pass morerapidly in one direction than the other.

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25. In a retarding device, a chamber adapted to contain a fluid, apiston movable back and forth in said chamber and dividing the same intocompartments, a by-pass which connects said compartments and conductsthe fluid alternately from one to the other upon moving said piston backand forth, and controlling means which are actuated by the fluid whichis pressed by said piston and which means move opposite to the piston.

26. In a retarding device, a chamber adapted to contain a fluid, apiston movable back and forth in said chamber and dividing the same intocompartments, a by-pass which connects said compartn'ients and con ductsthe fluid alternately from one to the other upon moving said piston backand f rth, regulating means which are actuated by the fluid which ispressed by said piston and adjusting means for said regulating meanswhereby the liquid may be permitted to flow more freely in one directionthan the other and the rate of flow in either direc tion may be variedindependently of the ot ier.

GUSTAV F. C. BAUER.

